The vacuum system for the superconducting linac of the TESLA Test Facility

Among the different approaches towards a next generation 500 GeV e + e − linear collider, the TESLA design uses superconducting accelerating structures operating at 1.3 GHz with a gradient of 25 MV/m. Presently, the TESLA test facility, which includes a prototype linear accelerator with superconducting cavities, is build up at DESY/Hamburg to serve as an R&D; tool. First, electrons have been accelerated in spring 1997. In the present state of the project two cryomodules, each containing eight solid niobium cavities are installed. One of the major objectives for the beam vacuum system is to preserve the cleanliness of the superconducting cavity surfaces and thus the operation at high gradients and high Q. Contamination by any sort of dust or condensation of gases during assembly and operation has to be absolutely avoided. Thus all vacuum components are carefully cleaned in clean rooms to make them particle free. Local clean rooms are used for installation of the components into the linac. A description of the linac vacuum system, the running experience and the present status of the project is given

The vacuum system for the superconducting linac of the TESLA Test Facility

Among the different approaches towards a next generation 500 GeV e + e − linear collider, the TESLA design uses superconducting accelerating structures operating at 1.3 GHz with a gradient of 25 MV/m. Presently, the TESLA test facility, which includes a prototype linear accelerator with superconducting cavities, is build up at DESY/Hamburg to serve as an R&D; tool. First, electrons have been accelerated in spring 1997. In the present state of the project two cryomodules, each containing eight solid niobium cavities are installed. One of the major objectives for the beam vacuum system is to preserve the cleanliness of the superconducting cavity surfaces and thus the operation at high gradients and high Q. Contamination by any sort of dust or condensation of gases during assembly and operation has to be absolutely avoided. Thus all vacuum components are carefully cleaned in clean rooms to make them particle free. Local clean rooms are used for installation of the components into the linac. A description of the linac vacuum system, the running experience and the present status of the project is given

New method to polarize protons in a storage ring and implications to polarize antiprotons

A feasibility test of a new method to polarize beams of strongly interacting charged particles circulating in a storage ring is described. The stored particles, here protons, pass through a polarized hydrogen gas target (thickness 6×1013 H/cm2) in the ring some 1010 times and become partially polarized because one spin state is attenuated faster than the other. The polarization buildup is clearly demonstrated in the present experiment

Detailed studies of a high-density polarized hydrogen gas target for storage rings

A high-density target of polarized atomic hydrogen gas for applications in storage rings was produced by injecting atoms from an atomic beam source into a T-shaped storage cell. The influence of the internal gas target on electron-cooled beams of 27 MeV α-particles and 23 MeV protons in the Heidelberg Test Storage Ring has been studied in detail. Target polarization and target thickness were measured by means of 27 MeV α-particles. For hyperfine states 1 + 2 a target thickness of n = (0.96±0.04) × 1014H→/cm2 was achieved with the cell walls cooled to 100 K. Working with a weak magnetic holding field (≈5 G) the maximum target polarization was PT = 0.84±0.02 when state 1 and PT = 0.46±0.01 when states 1 + 2 were injected. The target polarization was found to be constant over a period of 3 months with a net charge of Q ≈ 100C passing the storage cell